Improper port placement causes strange button mapping issues; why does this happen?

At our last tournament, we discovered that our ports had been improperly mapped out. This somehow caused issues, including

  • Buttons for our lift mapping to A and B (which are normally unused)
  • Smart Drivetrain only turning right when it should be turning left, and vice versa
  • Left side motor failing to operate, while also being set to the correct port

I am personally wondering why any of this could occur with improper port mapping.
The first thing I listed was of the most interest to me, because A and B were never used throughout the entire project or referenced in any way.
What with the ports could cause this. Motors that were on incorrect ports functioned on different buttons, instead of not functioning at all.

This has sufficiently confused me, and I just want to know why at this point.

Did you axedently run the preinstalled Drive program, instead of your normal one?

No. We never used a preinstalled drive program.